Production of nitrogen compounds.



:PATJENTED 001?. 13, 1903.

G; DE GHALMOT.

PRODUCTION OF NITROGEN COMPOUNDS.

APPLICATION TILED JAN. 23.1896.

3 SHEETSSHEET 1.

N0 MODEL.

INVENTOR:

FIG. 2.

(luclmiw (liq By his Al/or'ueys,

No. 741,396. PATENTED OCT. 13, 1903.

G; DE GHALMOT. PRODUCTION OF NITROGEN GOMPOUNDS.

APPLIOATION FILED JAN. 23. 1896.

N0 MODEL. 3 SHEETS-SHEET 2.

I ''FIG. 3.

PATENTED OCT. 13, 1903.

G. DE GHALMOT. PRODUCTION OF NITROGEN COMPOUNDS.

\ APPLIOATION FILED JAN. 23. 1896.

3 SHEETS-SHEET 3.

NO MODEL.

WITNESSES:

By his Alzomeys,

GUILLAUME DE CHALMOT,

TO THE WILLSON LABORATORY CORPORATION OF WEST VIRGINIA.

- Patented October 13, 190s.

PAT NT Fries;

or LEA'KSvILLE, NORTH CAROLINA, ASSIGNOR COMPANY, OF NEW YORK, N. Y., A

- PRODUCTION OF NITROGEN COMPOUNDS.

SPECIFICATION forming part of Letters Patent No. 741,396, dated October13, 1903.

Application filed January 23, 1896. Serial No. 576,521- (No specimens.)

To all whom, it may concern:

Be it known that 1, GUILLAUME DE CHAL- M01, 2. subject of the Queen ofthe Netherlands, (having declared my intention of becoming a citizen ofthe United States,') residing at Leaksville, in the county of Rockingham and State of North Carolina, have invented certaiu new and usefulImprovements in the Production of Nitrogen Compounds,

- IO of which the following is a specification.

This invention relates to the production of nitrids of metals ormetalloids in the electric furnace and the production of ammonia fromsuch nitride.

If oxids or salts of metals or metalloids are mixed with carbonaceousmatter and heated in the electric furnace while a current of nitrogen ispassed through the material, the metals or metalloids take upaconsiderable 2o amounto" nitrogen, which is bound in the form of nitridsalmost wholly, with occasional traces of cyanids. There can thus beObtained nitrids of calci n, (Oa N of barium, (Ba N Of aluminium, (AlN,and of titanium, (TiN In suchtests'I has a found the nitrids mixed withcarbids, oxids, and graphite or other-form of carbon. Definite formulaefor the reactions which take place cannot therefore be given. I havefounu that in these reactions it is not sufficient to pass the nitrogenOver the mass in the furnace; but it is practically essential that itshall be forced through the mass. In the case of fused material itbecomes exceedingly difficult in the electric furnace to effect apassage of the nitrogen through the mass so as to bring about anextensive contact between it and the molten material because of theextreme fluidity of the material at the excessively high temperatureattained. One purpose of my invention is to overcome this difficulty. Tothis end I conduct the reaction with an excess of carbon, whereby thematerial is rendered very porous, and thus the nitrogen can be forcedthrough the entire porous mass and brought into intimate contact withall the reduced metal. In fact, such a perfection of porosity is-thusattained as to render it feasible to introduce nitrogen on top of themass in the furnace and cause it to circulate downward through the mass.In order to obtain ammonia. -from these nitrogen compounds, they aretreated with steam at red heat. The steam should first be superheated;but if not it will become so by contact with the hot compounds. In thecase of barium, calcium, and other basic elements the ammonia is easilyobtained in this manner from their nitrids or cyanids. In the case oftitanium itis preferable to mix its nitrid with a basic o'xid and thensubject the mixture to superheated steam.

The treatment of the nitrids with steam for recovering the ammonia mightbe efiected at any time by heating the nitrid and then pass ing thesuperheated steam over or through it.

It is,-however, practically of great advantage to carry out thistreatment while the nitrogen compound is still'exposed to the heat ofthe electric furnace. I

My invention'therefore provides not only that the nitrogen shall beforced through the porous highly-heated mass in the furnace,' but alsothat superheated steam shall at the same time be forced through the massin order that the nitrogen which is fixed as a nitrid shall almostimmediately afterward be converted into ammonia. This Operation isgreatly facilitated by the porosity of the mass in' the furnace, whichrenders it feasible to institute a downward circulation of the gasesthrough the mass.

My invention further provides forasubstantiallycontinuous treatment inthe furnace by feedingit continuallywith fresh material from above andcausing the material under action to slowly descend at a rate to insurethat the greater part of the material shall be acted upon and reduced bythe electrically-generated heat in the furnace, the nitrogen beingintroduced at the top of the furnace and circulated downward past theelectrodes, and the superheated steam being introduced preferablybeneath the electrodes, the combined gases being thus circulateddownward through the porous mass and drawn 0d at any convenient pointbeneath, while the entire mass is caused to gradually descend and isfinally removedat the bottom of the furnace. I have devised 'anapparatusfor carwitha basic" oxid, preferably caustic lime, and also mixed withcarbonaceous material,-

preferably coke or' charcoal. The mixture is subjected to theheat of anelectric arc, and

nitrogen is forced through the semimolten' material. While still quitehot, steamis forced into the mixture. -The carbids and nitrids whichwere firstformed' are thus decomposed, and the originaloxids--that is,titanium oxid and caustic li ine.-are again obtained. The nitrogen formsammonia and the carbon forms carbon monoxid, while hydrogen is at thesame time liberated from the decomposition of ,the steam. The lime andtitanium oxid can then be mixed anew with carbon and used a second time.As some titanic acid is liable to be carried over with the gases whichpass out of the furnace and as this acid is somewhat expensive the gasesare conducted through settling-rooms and fines and washing apparatus,where all the titantum oxid'dust can settle. Some of the dust thusrecovered is titanium nitrid, which is volatilized in the arc.

Instead of titaniumoxid other oxidsmay be used. Alumina has given meespecially favorable results. Instead of lime other bases, like'sodaorpotash,would be equally efiective; but these are subject to theobjections of being too expensive, too'volatile, and of acting on thebricks of the furnace.

I will now describe the apparatus which I havedevis'ed for carrying outmy new process and which I believe is the best adapted to that end.

Figure lot the accompanying drawings is a vertical mid-section .throughthe electric furnace. Fig. 2 isahorizontal section thereof on the .line2 2 in Fig. 1. Fig. 3 is a vertical section on the line 3 3 in Fig. 2,showing the dust-separatorand ammonia-absorber. Figs. 4 and 5 arefragmentary sections showing two modified constructions for the lowerpart of the furnace shown in Fig. 1'. Fig. 6 is a sectional elevationshowing a'modified construction. i

7 Referring to Fig. 1, let A indicate an upright shaft, stack, orchimney, which may be made of masonry. In the upper part of this stackis formed a chamber B, constituting the chamber of the electricfurnace/Into this.

chamberproject electrodes C, consisting of bars, slabs, or pencils ofcarbon and which are constructed to be relatively movable throughopenings in oppositesides of the fur nace-wall in order to vary thelength of the are or the quantity of material interposed between thepencils and acted upon by the electric current passing between them.Both may be movable or one fixed and the other movable: Above thechamber B is mounted a hopper D, having a con trolling slide orfeeddoorEatits'bottom. Thishopperisdesigned to contain the pulverizedand mixed material to be fed to the furnace. Beneath the electrodes C Othefurnace-chamber B is preferably contracted 'or formed with ahopper-bottom, as shown at B, and from this portion the chamber extendsdownward, preferably, as an upright chamber of uniform cross-section.This chamber is designated F. In this chamber F, I have shown in Fig.1 apiston G, mounted .to work freely up or down in the chamber. andsupported on a rod 9, which is engaged between rollers g g one of whichis preferably formed with cog-teeth to engage corresponding rack-teethon one side of the rod g, so that by turning the wheels g g the pistonmay be raised or lowered. A pit g is provided for receiving the rod 9when the piston is lowered. The lowermost position of the piston isindicated indotted lines at G. Just abovethis position the stack isformed with an opening H, closed-by a suitable door.

A nitrogen pipe I enters the upper part of the furnace -chambe'r B forintroducing nitrogen thereinto. In practice I prefer to employatmospheric nitrogen in the form of what is'known as producer-gas orgeneratorgas consisting'of a, mixture chiefly of nitrogen and carbonmonoxid. I have shown in Fig. 1 a gas-producer J of ordinaryconstruction'and a blower K for forcing air through it, the producerbeing fed withcoal which is brought to'incandescence and the air thenforcedthrough-it in the well-known manner. The producer-gas thusgenerated is introduced into the chamber B and caused to flowdownthrough the mass of material. At any suitable point or points inthey lower part of the chamber B or upper part of the chamber F openingsor twye'rs a a are provided for introducing superheated steam. Steamis-fed to these openings through pipes S S, Fig. "2, which communicatewith passages a in the masonry, from which passages the twyers aabranch. ft

For permitting the escape of the gases from the chamber the furnace isformed on one or both sides with a perforated plate or partition I),from which leads an opening or space 0 in the masonry, and from thisextends a pipe d, which leads to the dust-separator L, Fig; 2. I haveshown the outlets bed as arrangedon'two opposite sides of the furnace.The plates b b may be made of porcelain or of metal, (ironl) In theformercase they may and in the latter case they must be cooled by thecirculation of cold water through them. In Fig. 2 I'haveshowntheleft-hand plate I) as made hollowfr this purpose. The right-hand plate(show n in plan) is supposed to be similarly constructed. Both platesare connected at the other side with an outlet water-pipe W. Thewater-current should be rapid bycircu lating the water under highpressure.

The dust-separator may be variously constructed. The construction shownin Fig. 3 consists of a casing L, into which the gases enter by pipesddat the top on opposite sides, are thence deflected downward bypartitions'e e, and flow thence upward to the inlet of'a pipe f, whichcarries the gases down out of the separator and delivers them to thegas-washer and ammonia-absorber.

For washing the gas it is caused to pass from the pipe f into a chamberg, which is sealed in water, so that the gas has to pass beneath thewater seal and bubble up through,

the water on the opposite side of a partition which separates thischamber from the chamber h. By this means any particles of dust whichhave not been caused to settle to the bottom of the dust-separator L arewashed out or arrested and retained in the water seal beneath thechambers g h.

For separating the ammonia from the gas any suitable kind ofammonia-absorber may. be employed--such, for example, as anyconstruction commonly used in gas-works for separating ammonia fromilluminating-gas. I have shown' at M one construction ofammonia-absorber that may be employed. It consists of an upright casingin which is ar ranged an alternating series of inclined shelvesz'i,extending each from one side across part way toward the other. In theconstruction shown the chamber 7i, already referred to,

constitutes the bottom chamber of this absorber. Cold water isintroduced by a pipe j and falls on the upper shelf 2', flowing acrossthis shelf and falling onto the next, flowing over this and falling ontothe next below, and

so on, the water thus having a zigzag course down the casingfand finallyfallinginto the water seal at the bottom in the chamber h. The gas whichbubbles up into the chamber 72 is caused to circulate in an 'upwardzigzag path, so that it-flows over the streams of water on the shelves 1t' and flows through. the successive waterfalls at the lower edges ofthese shelves, so that the gas continuously comes in contact with.fresher and cooler water, by which the ammonia contained in the.

rated plates b. The titanic oxid or other me tallic oxid, the lime orother base, and the carbon having been pulverized and mixed together areplaced in the hopper D. Suificient material is caused to fall fromthishopper into the chamber 13 to fill the furnace up to and around theelectrodes 0 C. The furnace operation can then begin. The electrodes C 0being connected at the opposite. terminals of an electric circuit fed bya suitable generator or transformer, (either continuous or f airbeingsucked into the furnacethat is to say, its pressure is slightlymore than that of the atmosphere. The suction-blower N is set inoperation, being driven at such speed as to generate just sufficientsuction to draw the gas through the mass of pulverulent material inthefurnace and through the dust-separator L and ammonia absorber M.Consequently the gas introducedat I under substautially atmosphericpressure is drawn down through the porous mass by suction.

The action of the electrically-generated heat in the furnace is'toreduce the metallic oxid and the basicloxid, the incandescent reducedmaterials being'expo'sed to the nitrogen of the producergas, and therebyconverted partly into nitrids and partly into carbide.

As fast as this reduction occurs the piston G should be lowered byturning the wheels g 9 and fresh material should be introduced from thehopper D by opening the. slide E.

Any other means for feeding the'm'aterial maybe substituted-for thisslide.v In this way a sufficient mass of unreduced material is keptpiled above the electrodes,while the nitrids and carbids are continuallycaused to descend to positions opposite the twyers aa'andoutlet-openings b b. As soon as the nitrids,&c.,

have come to the level of the twyers superheated steam should be turnedon through the pipes S S and injected through these twyers into thematerial. This steam decomposes the nitrids, generating ammonia andhydrogen, which, with the residue of the producer-gas, is drawn offthrough the perforations b-and passed through the dust-separator, whereany particles of dust 'or ashes, in-- cluding particles of titanic acid,are caused to settle. The gases th'en pass'down through the pipe f tothe water-chamber-g, where they are forced throughwater to takeout anyfurther particles ,of dust. The gases then pass upward through theammonia-absorber,where the ammoniais taken up by the water. Theremaining gas then passes out through the pipe 7c and blower N andbeinga combustible gas sustantially devoid of nitrogen it may beconducted to gas-burners or anyap-l paratus in which such gas can be:utilized. Thefurnaceoperation continues as described until the piston Ghas descended toits lowest position G, whereupon the furnace operationIIC is stopped, and as soon as the mass is suliiciently cooled the doorH is opened and the material is drawn out through this door. Thismaterial consists of substantially the original mixture of metallic oxidand lime and may :be used again by grinding it and mixing it again withcarbon.

which is required chemicallyto eflect'the re-' duction of the metallicoxid the reduced ma terial in the-furnaceis made very porous.

This-is especially important in the use of titanium, since its nitridhas all the properties ofa metal and has a very high fusing-point,

so that it is very desirable to keep its particles apart. The porosityis further promoted by the mixture of "titanium oxidwith lime,

whichafterreduction forms a mixture of ti-' tanic nitrid, calciumcarbid, and calcium nitrid. The steam on coming in contact with thecalcium carbid and nitrid decomposes these compounds at once,formingcalcium oxid and gases like carbon monoxid, carbon dioxid,hydrogen, ammonia, &c; The drivihg ofi of these gases makes the materialstill more porous, since .the calcium oxid which is thus reconstitutedis not hot enough to run together. The resulting porosity of thematerial allows the steam to come also into contact with the titanicnitrid, which would not occur if this latter were alone present, sincein that case thewater-vaporwould act only on the surface of this nitrid,forming titanic acid, which would withstand the further action of thevapor. It is also probable that the presence of the base (lime) furthersthe decomposition of the titanic ni'trid by uniting with a part of theresulting titanic acid;

, The reaction between superheated steam and titanium nitrid is Ti N-l-6H Q=3TiO +etNH The. efiect of adding a base, as soda oriim'e,

' is that it unites with the titanic oxid that is set free by the steamand forms a salt called a titanate', (titanic oxid having acid.properties,) the reaction being as follows, with soda:

ner'shown in Fig. 4 by constituting a screw conveyer P for the piston G,this conveyer acting to continuously or intermittently dig out thematerial from the bottom of the chamber F, so that the process may bemade, in

is suggested in Fig. 5 may beemployedgwhere the mass settles down to thebottom of thechamber F and can be shoveled out through eifect,continuous, or such a construction as v a door Q, its descent beingfacilitated by polzing through a poke-opening Q.

Fig; 6 shows a'modified construction of furnace wherein a tubular carbonpencil C is used as one electrode and an iron plate 0 forming the bottomof the furnace-chamber and covered with a layer of carbon, constitutesthe other electrode, these being connected iln circuit with a dynamo orother generator Din the ordinary manner. Nitrogen orproducer-gas isintroduced through a pipe being conducted under control of valves 10 and11 through a'flexible pipe R to thehol- 'Iand superheated steam throughapipe-S', either of these in alternation or bothtogether low in thecarbon pencil 0', the gases flowing down through this carbon pencil tothe bottom thereof and then ascending through the mass of material inthe furnace and passing out through a piped, which leads to any suitabledust-separator and ammonia-absorber.

This apparatus may-he. operated by first circulating nitrogen throughthe furnace during the maintenance of the are and then discontinuing thearc and circulating superheated steam through the highly-heated mass inthe the operations altercarrying out the process... It is within myinvention to effect the preliminary heating of the materials by heatotherwisev generatedas, for example, in any ordinary furnace heated bycombustion-thus raising the materials to "as high a temperature as ispracticable by such means and then subjecting them to the action of anelectric arc to further raise the temperature to that necessary toaccomplish the conversion of the oxid or u salt into a nitrid, cyanid orcarbid..

This process has the advantage of saving a part of theelectrically-generated heat, which is' expensive, and substituting forit heat generated fromfuel.

I claim as my invention the following'defined novel features,substantially as hereinbefore specified, namely:

1. The process which consists-in heating the oxid or salt of a metal ormetalloid with an" excess of carbonaceous matter in an electric furnace,so as to reduce the, metal or metalloid while forming a porous permeablemass,and passing nitrogen through the heated porous mass at so high atemperature as to form a nitrid rather than a cyan'id of the metal ormetalloid. Q

2. The process which consists in heating the oxid or salt of-a metalormetalloid with anexcess of carbonaceous matter in an electric furnace,so'as to reduce the metal whileforming'a porous permeable .mass,simultaneously passing nitrogen through the heated. porous'mass whilemaintaining so high a tern;- perature as toformfa nitrid rather than acyanid of the metal or metalloid, and 'subsequently passing superheatedsteam through the porous; mass to decompose-t the nitrid and formammonia. 1

.3 -The process which c'onsistsin heating theo'xidior salt of a metal ormetalloid with carbonaceous matter in an electric furnace so as toreduce the metal or metalloid, passingnitrogen th ough the heated massawhile maintainingso igha temperature as to form a nitrid rather thanacyanid of the metalor metalloid, and while the massis stillhighlyheated passing superheated steam through" it 3 to decompose thenitridand form ammonia. I

4, The process which consists in heating thejoxid' or salt of a metal ormetalloid with an added base and, with carbonace'ousimatter in anelectric furnace,' so as. to reducethe metal or metalloid and convertthe baseinto a earbid, simultaneously passingnitrogen.

throughv the material'while maintaining: so

high a temperature as toform a nitrid rather than a cyanid, andsubsequently exposing the material to superheated steam to dQCOUI'. posethe nitrid and form ammonia.

5. The process which consists in heatinga titaniferous compound with anadded base I and carbonaceous matter in an electric furnace, so as toreduce the titanium, and passmaintaining so high a temperature as toform a mixture of titanic and basic nitrids (rather than cyanide) orcarbids, and subsequently exposing these'to superheated steam to de- Icompose the nitrids andform ammonia,-

'.cyanid of the metal. i

9. The processivhich consists in exposing 7. The process which consistsin heating a titaniferouscompound with lime and carbonaceons matter inan electric furnae; passing nitrogen through the material inthe'furnaceunder so high atemperature asto formgfaii trids, whereby. isformed a mixfiifiiot titanic and calcic nitrids and .galcium carbid, and

subsequently exposing these to superheated steam to decompose thenitridsand form ammonia. I

8. The process which consists in exposing a mixture of .the oxid or saltof a metal or metalloid with. carbonaceous matter to the heat generatedby the passage of an electric current between electrodes, whereby themetal is' reduced, causing the mass to dc scend inproportionas thereduction takes I efiect to bring fresh material within the action ofthe current, and to lower the reduced materiaLb'eyond the electrodes,and passing a current-of nitrogen downwardly through the mass, wherebyit is brought into contact with the metal or metalloid, at the instantof its reduction; while maintaining so high a-tem perature as to forma'nitrid rather than a a m-ixture of the oxid or salt of a metal ormetalloid with carbonaceous matter v to the heat generated by thepassageofan electric current between electrodes, whereby the metal ormetalloid is reduced, causing the mass to descend in proportion as thereduc tion takes eflect to bring fresh material withl in the action ofthe current, and to lower the reduced material beyond the electrodes,passing a current of nitrogen downwardly through the mass, whereby it isbrought intoco'ntact with-the metal or metalloid attheinstant'of itsreduction while maintaining so,high a temperature as to form a nitridrather than a cyanid of the metal or metalloid, and simultaneouslyintroducing superheatedsteam into the: mass in contact with thenewly-formed nitridto decompose the same and form ammon ia.

In witness whereofI have hereunto signed my name in'the presence of twosubscribingw witnesses. I

V GUILLAUME DE- CHALMOT. I Witnesses: I

E. B. KING,

CA VIN SHARP.

